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   Phil (ascentale) (ascentale@sfba.social)'s status on Sunday, 29-Dec-2024 20:21:30 JST Phil (ascentale)

   • Solarbird :flag_cascadia:

   @moira asks:

   Q6. Have you seen this dual-chain redundant drive system and would you want one?

   (If not, have you seen any ultra-reliable designs or other unconventional drivetrains)

   https://newatlas.com/bicycles/two-chain-buffalo-bike/

   #BikeNite #BikeNiteQ

   • Bob Jonkman repeated this.
   • Embed this notice
     nick (nickzoic@aus.social)'s status on Sunday, 29-Dec-2024 20:21:50 JST nick

     in reply to

     • Sam Whited
     • Solarbird :flag_cascadia:

     @sam @ascentale @moira It sounds like the magic bit is in the freewheel so you'd be able to swap out chainrings to suit your needs.

     https://www.cyclingweekly.com/news/its-an-engineering-feat-why-this-22kg-bicycle-has-two-chains

     I haven't found the patent number yet though ...

     Bob Jonkman repeated this.
   • Embed this notice
     nick (nickzoic@aus.social)'s status on Sunday, 29-Dec-2024 20:21:50 JST nick

     in reply to

     • Sam Whited
     • Solarbird :flag_cascadia:

     @sam @ascentale @moira Update: https://patents.google.com/patent/US11655004B2/en

   • Embed this notice
     Sam Whited (sam@social.coop)'s status on Sunday, 29-Dec-2024 20:21:51 JST Sam Whited

     in reply to

     • Solarbird :flag_cascadia:

     @ascentale @moira I love the original Buffalo bicycles, but I didn't know they'd done an update. The dual chain thing makes sense to me, though I'd worry about the availability of parts: when you wear down that chainring, where do you get another one with whatever weird setup that has?

     I have worked on a few shaft-drive bicycles and, though I really liked them, I always felt the same about those (too hard to find replacement parts).

     #BikeNite

   • Embed this notice
     Bob Jonkman (bobjonkman@mastodon.sdf.org)'s status on Sunday, 29-Dec-2024 20:30:59 JST Bob Jonkman

     in reply to

     • Sam Whited
     • nick
     • Solarbird :flag_cascadia:

     #BikeNite A6: I read about this dual chain, dual speed bike hub a few months ago. The article I read wasn't kind. And @nickzoic hits the main problem: It's patented, proprietary technology. While that may be OK for wealthy cyclists living within shipping range of a licenced repair depot, it's particularly ill-suited to poor, remotely located, developing countries. A bog-standard bike with parts interchangeable with most other bikes is better suitec there.

     @sam @ascentale @moira

   • Embed this notice
     moggie (everydaymoggie@sfba.social)'s status on Monday, 30-Dec-2024 04:59:47 JST moggie

     in reply to

     • Solarbird :flag_cascadia:

     Q6. Have you seen this dual-chain redundant drive system and would you want one?
     (If not, have you seen any ultra-reliable designs or other unconventional drivetrains)

     The unconventional drivetrains thing reminded me of these videos. Some of these drivetrains are downright bizarre. Strings? Who would ever think of doing that?
     https://www.youtube.com/watch?v=3BHiZnB53pY
     https://www.youtube.com/watch?v=DJYVkVfrl2Y
     https://www.youtube.com/watch?v=r-Zyp6jX0HM
     https://www.youtube.com/watch?v=doKhd8kE0Ow

     #BikeNite
     @ascentale @moira

   • Embed this notice
     nick (nickzoic@aus.social)'s status on Monday, 30-Dec-2024 05:54:03 JST nick

     in reply to

     • Sam Whited
     • Bob Jonkman
     • Solarbird :flag_cascadia:

     @bobjonkman @sam @ascentale @moira I mean, that could be okay, *IF* the magic doodad is cheap enough for the target market *AND* you can just drop it in like a freewheel cassette, that's pretty cool.

     A little shop could keep a pile of doodads and a pile of chains on hand and do conversions with only hand tools. The double chain thing is weird but it does allow for different ratios by fitting different chain rings, and unlike, eg: Sturmey-Archer or Shimano Nexus 3-speeds it doesn't need any torque reaction from the dropouts.

     (It occurs to me, though, that any frame with dropouts wide enough for a freewheel / this thing is going to have the wrong kind of dropouts for chain tensioning, and also how do you tension both chains at once, unless you're just lucky I suppose?)

     Anyway: It'd be a nice problem to solve, because there's a shitload of old bikes out there with decent frames and reasonable wheels, and there are charities already which ship these to developing countries where they can be turned into solid bikes *but* most of their derailleurs were a mess already and the rest are bent because that's what you get when you make a big pile of bikes at the municipal tip.

     Bicycles are basically free. Useful bicycles are a bit more ...

     Bob Jonkman repeated this.
   • Embed this notice
     nick (nickzoic@aus.social)'s status on Monday, 30-Dec-2024 07:30:04 JST nick

     in reply to

     • Sam Whited
     • Bob Jonkman
     • Solarbird :flag_cascadia:

     @bobjonkman @sam @ascentale @moira oh yeah I had another look at the pics on the website and it uses backwards-facing, screw-adjusted dropouts. So that's not going to work with all the 3x7 frames in the recycling pile.

     Also that's one chain adjustment for two chains, so the choice of chainrings is going to be limited by what gets both chains to the same length, and also the more-heavily-used chain is going to get loose as it wears, and you can't adjust it because the other chain is then too tight.

     I was thinking about whether a pair of idlers would work: I've seen idlers used for single-speed conversions and they seem pretty good, I guess you could extend the idea to 2 chains. A sprung idler might not work well with the back-pedal gear shifts though, and two separate fixed idlers would be a bit of a maintenance headache!